1. Field of the Invention
The present invention relates to the gene of the hop mosaic virus (abbreviated as HMV hereafter) and diagnostic methods for detecting HMV.
2. Description of the Background
HMV, a pathogenic virus of hop, is a filamentous shaped virus comprising a single stranded RNA genome and belongs to the same carlavirus group as the hop latent virus. HMV is an important causative pathogen of mosaic symptom to susceptible hop cultivars [Probasco and Skotland, Can. J. Microbiol. 22: 116011162 (1976); Adams and Barbara, Ann. Appl. Biol. 96: 201208 (1980); Adams and Barbara, Ann. Appl. Biol. 101: 495500 (1982); Yu and Liu, Plant Pathology 36: 3844 (1987); Kanno et al., Ann. Phytopath. Soc. Japan 680 (1994)]. Therefore, for the production of hop, surveys of fields which are not contaminated with this virus and inspections of virus-free seedlings are performed.
Conventionally, for the confirmation of virus-free seedlings and the field survey to prevent the viral reinfection immunodiagnostic methods such as ELISA have been employed. However, HMV diagnosis by ELISA poses various problems such as difficulties in the preparation as well as availability of antibodies. Furthermore, even though antibodies are available, ELISA still poses problems such as inferior accuracy of diagnostic results due to nonspecific reactions of the antibodies.
On the other hand, since gene sequences of various viruses have been elucidated owing to the recent progress in molecular biology, certain species of viruses can be accurately detected and diagnosed using genetic engineering techniques. However, the detection of HMV has relied upon the above-mentioned immunological procedure, because its gene sequences have not been elucidated.
Therefore, the present inventors have actively pursued efforts to isolate and purify the HMV gene and elucidate its base sequence. Furthermore, they have developed methods for detecting HMV using such nucleic acid sequences.